1
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Yang J, Hediyal TA, Chidambaram SB, Kaul-Ghanekar R, Sakharkar MK. Benzyl isothiocyanate as an alternative to antibiotics? a comparative in vivo study using Pseudomonas aeruginosa infection as a model. PLoS One 2024; 19:e0303490. [PMID: 38753636 PMCID: PMC11098397 DOI: 10.1371/journal.pone.0303490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 04/14/2024] [Indexed: 05/18/2024] Open
Abstract
Due to over-prescription of antibiotics, antimicrobial resistance has emerged to be a critical concern globally. Many countries have tightened the control of antibiotic usage, which, in turn, promotes the search for alternatives to antibiotics. Quite a few phytochemicals have been investigated. Benzyl isothiocyanate (BITC) is an important secondary metabolite in cruciferous species and exhibited potent antimicrobial activity under in vitro conditions. In this research, we undertook a comparative mouse model study of BITC with gentamycin sulfate (positive antibiotic control) and ceftiofur hydrochloride (negative antibiotic control) against Pseudomonas aeruginosa infection. Our results showed that BITC exhibited comparable or better antimicrobial activity and lower infiltration of mouse immune cells upon comparing to gentamycin sulfate. Furthermore, BITC did not impose any toxicity to the air pouch skin tissues. In summary, our current study suggests that BITC could be an alternative to antibiotics and deserves further in vivo and clinical trial studies.
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Affiliation(s)
- Jian Yang
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Tousif Ahmed Hediyal
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, Karnataka, India
- Center for Experimental Pharmacology and Toxicology, JSS Academy of Higher Education & Research, Mysuru, Karnataka, India
| | - Saravana Babu Chidambaram
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, Karnataka, India
- Center for Experimental Pharmacology and Toxicology, JSS Academy of Higher Education & Research, Mysuru, Karnataka, India
| | - Ruchika Kaul-Ghanekar
- Cancer Research Lab, Symbiosis School of Biological Sciences (SSBS), Symbiosis Centre for Research and Innovation (SCRI), Symbiosis International (Deemed University), Pune, Maharashtra, India
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2
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Guo H, Geddes EJ, Opperman TJ, Heuck AP. Cell-Based Assay to Determine Type 3 Secretion System Translocon Assembly in Pseudomonas aeruginosa Using Split Luciferase. ACS Infect Dis 2023; 9:2652-2664. [PMID: 37978950 DOI: 10.1021/acsinfecdis.3c00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Multi-drug-resistant Pseudomonas aeruginosa poses a serious threat to hospitalized patients. This organism expresses an arsenal of virulence factors that enables it to readily establish infections and disseminate in the host. The Type 3 secretion system (T3SS) and its associated effectors play a crucial role in the pathogenesis of P. aeruginosa, making them attractive targets for the development of novel therapeutic agents. The T3SS translocon, composed of PopD and PopB, is an essential component of the T3SS secretion apparatus. In the properly assembled translocon, the N-terminus of PopD protrudes into the cytoplasm of the target mammalian cell, which can be exploited as a molecular indicator of functional translocon assembly. In this article, we describe a novel whole-cell-based assay that employs the split NanoLuc luciferase detection system to provide a readout for translocon assembly. The assay demonstrates a favorable signal/noise ratio (13.6) and robustness (Z' = 0.67), making it highly suitable for high-throughput screening of small-molecule inhibitors targeting T3SS translocon assembly.
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Affiliation(s)
- Hanling Guo
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Emily J Geddes
- Microbiotix, Inc., Worcester, Massachusetts 01605, United States
| | | | - Alejandro P Heuck
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, United States
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3
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Elmassry MM, Colmer-Hamood JA, Kopel J, San Francisco MJ, Hamood AN. Anti- Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials. Microorganisms 2023; 11:916. [PMID: 37110338 PMCID: PMC10144840 DOI: 10.3390/microorganisms11040916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.
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Affiliation(s)
- Moamen M. Elmassry
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Jane A. Colmer-Hamood
- Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Jonathan Kopel
- Department of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Michael J. San Francisco
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
- Honors College, Texas Tech University, Lubbock, TX 79409, USA
| | - Abdul N. Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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4
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Hastings CJ, Himmler GE, Patel A, Marques CNH. Immune Response Modulation by Pseudomonas aeruginosa Persister Cells. mBio 2023; 14:e0005623. [PMID: 36920189 PMCID: PMC10128020 DOI: 10.1128/mbio.00056-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Bacterial persister cells-a metabolically dormant subpopulation tolerant to antimicrobials-contribute to chronic infections and are thought to evade host immunity. In this work, we studied the ability of Pseudomonas aeruginosa persister cells to withstand host innate immunity. We found that persister cells resist MAC-mediated killing by the complement system despite being bound by complement protein C3b at levels similar to regular vegetative cells, in part due to reduced bound C5b, and are engulfed at a lower rate (10- to 100-fold), even following opsonization. Once engulfed, persister cells resist killing and, contrary to regular vegetative cells which induce a M1 favored (CD80+/CD86+/CD206-, high levels of CXCL-8, IL-6, and TNF-α) macrophage polarization, they initially induce a M2 favored macrophage polarization (CD80+/CD86+/CD206+, high levels of IL-10, and intermediate levels of CXCL-8, IL-6, and TNF-α), which is skewed toward M1 favored polarization (high levels of CXCL-8 and IL-6, lower levels of IL-10) by 24 h of infection, once persister cells awaken. Overall, our findings further establish the ability of persister cells to evade the innate host response and to contribute chronic infections. IMPORTANCE Bacterial cells have a subpopulation-persister cells-that have a low metabolism. Persister cells survive antimicrobial treatment and can regrow to cause chronic and recurrent infections. Currently little is known as to whether the human immune system recognizes and responds to the presence of persister cells. In this work, we studied the ability of persister cells from Pseudomonas aeruginosa to resist the host defense system (innate immunity). We found that this subpopulation is recognized by the defense system, but it is not killed. The lack of killing likely stems from hindering the immune response regulation, resulting in a failure to distinguish whether a pathogen is present. Findings from this work increase the overall knowledge as to how chronic infections are resilient.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Grace Elizabeth Himmler
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Arpeet Patel
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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5
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Pan X, Liang H, Zhao X, Zhang Q, Chen L, Yue Z, Yin L, Jin Y, Bai F, Cheng Z, Bartlam M, Wu W. Regulatory and structural mechanisms of PvrA-mediated regulation of the PQS quorum-sensing system and PHA biosynthesis in Pseudomonas aeruginosa. Nucleic Acids Res 2023; 51:2691-2708. [PMID: 36744476 PMCID: PMC10085694 DOI: 10.1093/nar/gkad059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa is capable of causing acute and chronic infections in various host tissues, which depends on its abilities to effectively utilize host-derived nutrients and produce protein virulence factors and toxic compounds. However, the regulatory mechanisms that direct metabolic intermediates towards production of toxic compounds are poorly understood. We previously identified a regulatory protein PvrA that controls genes involved in fatty acid catabolism by binding to palmitoyl-coenzyme A (CoA). In this study, transcriptomic analyses revealed that PvrA activates the Pseudomonas quinolone signal (PQS) synthesis genes, while suppressing genes for production of polyhydroxyalkanoates (PHAs). When palmitic acid was the sole carbon source, mutation of pvrA reduced production of pyocyanin and rhamnolipids due to defective PQS synthesis, but increased PHA production. We further solved the co-crystal structure of PvrA with palmitoyl-CoA and identified palmitoyl-CoA-binding residues. By using pvrA mutants, we verified the roles of the key palmitoyl-CoA-binding residues in gene regulation in response to palmitic acid. Since the PQS signal molecules, rhamnolipids and PHA synthesis pathways are interconnected by common metabolic intermediates, our results revealed a regulatory mechanism that directs carbon flux from carbon/energy storage to virulence factor production, which might be crucial for the pathogenesis.
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Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Han Liang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China
| | - Xinrui Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qionglin Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China
| | - Lei Chen
- Department of Plant Biology and Ecology, College of Life Science Nankai University, Tianjin 300071 China
| | - Zhuo Yue
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Liwen Yin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.,Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin 300071, China.,Nankai International Advanced Research Institute (Shenzhen Futian), Shenzhen, Guangdong 518045, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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6
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Hastings CJ, Himmler GE, Patel A, Marques CNH. Immune response modulation by Pseudomonas aeruginosa persister cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.07.523056. [PMID: 36711557 PMCID: PMC9881899 DOI: 10.1101/2023.01.07.523056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Bacterial persister cells - a metabolically dormant subpopulation tolerant to antimicrobials - contribute to chronic infections and are thought to evade host immunity. In this work, we studied the ability of Pseudomonas aeruginosa persister cells to withstand host innate immunity. We found that persister cells resist MAC-mediated killing by the complement system despite being bound by complement protein C3b at levels similar to regular vegetative cells, in part due to reduced bound C5b - and are engulfed at a lower rate (10-100 fold), even following opsonization. Once engulfed, persister cells resist killing and, contrary to regular vegetative cells which induce a M1 favored (CD80+/CD86+/CD206-, high levels of CXCL-8, IL-6, and TNF-α) macrophage polarization, they initially induce a M2 favored macrophage polarization (CD80+/CD86+/CD206+, high levels of IL-10, and intermediate levels of CXCL-8, IL-6, and TNF-α), which is skewed towards M1 favored polarization (high levels of CXCL-8 and IL-6, lower levels of IL-10) by 24 hours of infection, once persister cells awaken. Overall, our findings further establish the ability of persister cells to evade the innate host response and to contribute chronic infections.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Grace Elizabeth Himmler
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Arpeet Patel
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
- Corresponding author:
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7
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Wood SJ, Goldufsky JW, Seu MY, Dorafshar AH, Shafikhani SH. Pseudomonas aeruginosa Cytotoxins: Mechanisms of Cytotoxicity and Impact on Inflammatory Responses. Cells 2023; 12:cells12010195. [PMID: 36611990 PMCID: PMC9818787 DOI: 10.3390/cells12010195] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 01/05/2023] Open
Abstract
Pseudomonas aeruginosa is one of the most virulent opportunistic Gram-negative bacterial pathogens in humans. It causes many acute and chronic infections with morbidity and mortality rates as high as 40%. P. aeruginosa owes its pathogenic versatility to a large arsenal of cell-associated and secreted virulence factors which enable this pathogen to colonize various niches within hosts and protect it from host innate immune defenses. Induction of cytotoxicity in target host cells is a major virulence strategy for P. aeruginosa during the course of infection. P. aeruginosa has invested heavily in this strategy, as manifested by a plethora of cytotoxins that can induce various forms of cell death in target host cells. In this review, we provide an in-depth review of P. aeruginosa cytotoxins based on their mechanisms of cytotoxicity and the possible consequences of their cytotoxicity on host immune responses.
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Affiliation(s)
- Stephen J. Wood
- Department of Medicine, Division of Hematology, Oncology and Cell Therapy, Rush University Medical Center, Chicago, IL 60612, USA
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL 60612, USA
| | - Josef W. Goldufsky
- Department of Medicine, Division of Hematology, Oncology and Cell Therapy, Rush University Medical Center, Chicago, IL 60612, USA
| | - Michelle Y. Seu
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL 60612, USA
| | - Amir H. Dorafshar
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL 60612, USA
| | - Sasha H. Shafikhani
- Department of Medicine, Division of Hematology, Oncology and Cell Therapy, Rush University Medical Center, Chicago, IL 60612, USA
- Department of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL 60612, USA
- Cancer Center, Rush University Medical Center, Chicago, IL 60612, USA
- Correspondence:
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8
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Impact of fluoroquinolones and aminoglycosides on P. aeruginosa virulence factor production and cytotoxicity. Biochem J 2022; 479:2511-2527. [PMID: 36504127 DOI: 10.1042/bcj20220527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is one of leading causes of disability and mortality worldwide and the world health organisation has listed it with the highest priority for the need of new antimicrobial therapies. P. aeruginosa strains responsible for the poorest clinical outcomes express either ExoS or ExoU, which are injected into target host cells via the type III secretion system (T3SS). ExoS is a bifunctional cytotoxin that promotes intracellular survival of invasive P. aeruginosa by preventing targeting of the bacteria to acidified intracellular compartments. ExoU is a phospholipase which causes destruction of host cell plasma membranes, leading to acute tissue damage and bacterial dissemination. Fluoroquinolones are usually employed as a first line of therapy as they have been shown to be more active against P. aeruginosa in vitrothan other antimicrobial classes. Their overuse over the past decade, however, has resulted in the emergence of antibiotic resistance. In certain clinical situations, aminoglycosides have been shown to be more effective then fluoroquinolones, despite their reduced potency towards P. aeruginosa in vitro. In this study, we evaluated the effects of fluoroquinolones (moxifloxacin and ciprofloxacin) and aminoglycosides (tobramycin and gentamycin) on T3SS expression and toxicity, in corneal epithelial cell infection models. We discovered that tobramycin disrupted T3SS expression and reduced both ExoS and ExoU mediated cytotoxicity, protecting infected HCE-t cells at concentrations below the minimal inhibitory concentration (MIC). The fluoroquinolones moxifloxacin and ciprofloxacin, however, up-regulated the T3SS and did not inhibit and may have increased the cytotoxic effects of ExoS and ExoU.
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9
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Bagayoko S, Meunier E. Emerging roles of ferroptosis in infectious diseases. FEBS J 2022; 289:7869-7890. [PMID: 34670020 DOI: 10.1111/febs.16244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/06/2021] [Accepted: 10/20/2021] [Indexed: 01/14/2023]
Abstract
In living organisms, lipid peroxidation is a continuously occurring cellular process and therefore involved in various physiological and pathological contexts. Among the broad variety of lipids, polyunsaturated fatty acids (PUFA) constitute a major target of oxygenation either when released as mediators by phospholipases or when present in membranous phospholipids. The last decade has seen the characterization of an iron- and lipid peroxidation-dependent cell necrosis, namely, ferroptosis, that involves the accumulation of peroxidized PUFA-containing phospholipids. Further studies could link ferroptosis in a very large body of (physio)-pathological processes, including cancer, neurodegenerative, and metabolic diseases. In this review, we mostly focus on the emerging involvement of lipid peroxidation-driven ferroptosis in infectious diseases, and the immune consequences. We also discuss the putative ability of microbial virulence factors to exploit or to dampen ferroptosis regulatory pathways to their own benefit.
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Affiliation(s)
- Salimata Bagayoko
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, France
| | - Etienne Meunier
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, France
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10
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Jouault A, Saliba AM, Touqui L. Modulation of the immune response by the Pseudomonas aeruginosa type-III secretion system. Front Cell Infect Microbiol 2022; 12:1064010. [PMID: 36519135 PMCID: PMC9742435 DOI: 10.3389/fcimb.2022.1064010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/15/2022] [Indexed: 11/29/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can cause critical cellular damage and subvert the immune response to promote its survival. Among the numerous virulence factors of P. aeruginosa, the type III secretion system (T3SS) is involved in host cell pathogenicity. Using a needle-like structure, T3SS detects eukaryotic cells and injects toxins directly into their cytosol, thus highlighting its ability to interfere with the host immune response. In this mini-review, we discuss how the T3SS and bacterial effectors secreted by this pathway not only activate the immune response but can also manipulate it to promote the establishment of P. aeruginosa infections.
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Affiliation(s)
- Albane Jouault
- Mucoviscidose: Phénotypique et Phénogénomique, Centre de Recherche Saint-Antoine, Sorbonne Universités, UPMC Univ Paris 06, INSERM, Paris, France,Département Santé Globale, Mucoviscidose et Bronchopathie Chroniques, Institut Pasteur, Paris, France,*Correspondence: Albane Jouault,
| | - Alessandra Mattos Saliba
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Lhousseine Touqui
- Mucoviscidose: Phénotypique et Phénogénomique, Centre de Recherche Saint-Antoine, Sorbonne Universités, UPMC Univ Paris 06, INSERM, Paris, France,Département Santé Globale, Mucoviscidose et Bronchopathie Chroniques, Institut Pasteur, Paris, France
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11
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Constantino-Teles P, Jouault A, Touqui L, Saliba AM. Role of Host and Bacterial Lipids in Pseudomonas aeruginosa Respiratory Infections. Front Immunol 2022; 13:931027. [PMID: 35860265 PMCID: PMC9289105 DOI: 10.3389/fimmu.2022.931027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa is one of the most common agents of respiratory infections and has been associated with high morbidity and mortality rates. The ability of P. aeruginosa to cause severe respiratory infections results from the coordinated action of a variety of virulence factors that promote bacterial persistence in the lungs. Several of these P. aeruginosa virulence mechanisms are mediated by bacterial lipids, mainly lipopolysaccharide, rhamnolipid, and outer membrane vesicles. Other mechanisms arise from the activity of P. aeruginosa enzymes, particularly ExoU, phospholipase C, and lipoxygenase A, which modulate host lipid signaling pathways. Moreover, host phospholipases, such as cPLA2α and sPLA2, are also activated during the infectious process and play important roles in P. aeruginosa pathogenesis. These mechanisms affect key points of the P. aeruginosa-host interaction, such as: i) biofilm formation that contributes to bacterial colonization and survival, ii) invasion of tissue barriers that allows bacterial dissemination, iii) modulation of inflammatory responses, and iv) escape from host defenses. In this mini-review, we present the lipid-based mechanism that interferes with the establishment of P. aeruginosa in the lungs and discuss how bacterial and host lipids can impact the outcome of P. aeruginosa respiratory infections.
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Affiliation(s)
- Pamella Constantino-Teles
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Albane Jouault
- Sorbonne Université, Centre de Recherche Saint-Antoine, Inserm, Institut Pasteur, Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Paris, France
| | - Lhousseine Touqui
- Sorbonne Université, Centre de Recherche Saint-Antoine, Inserm, Institut Pasteur, Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Paris, France
| | - Alessandra Mattos Saliba
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil
- *Correspondence: Alessandra Mattos Saliba,
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12
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Li H, Xia Y, Tian Z, Jin Y, Bai F, Cheng Z, Swietnicki W, Wu W, Pan X. Dihydrolipoamide Acetyltransferase AceF Influences the Type III Secretion System and Resistance to Oxidative Stresses through RsmY/Z in Pseudomonas aeruginosa. Microorganisms 2022; 10:microorganisms10030666. [PMID: 35336241 PMCID: PMC8950878 DOI: 10.3390/microorganisms10030666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/10/2022] [Accepted: 03/17/2022] [Indexed: 01/27/2023] Open
Abstract
Carbon metabolism plays an important role in bacterial physiology and pathogenesis. The type III secretion system (T3SS) of Pseudomonas aeruginosa is a virulence factor that contributes to acute infections. It has been demonstrated that bacterial metabolism affects the T3SS. Meanwhile, expression of T3SS genes is negatively regulated by the small RNAs RsmY and RsmZ. In this study, we studied the relationship between the dihydrolipoamide acetyltransferase gene aceF and the T3SS. Our results reveal an upregulation of RsmY and RsmZ in the aceF mutant, which represses the expression of the T3SS genes. Meanwhile, the aceF mutant is more tolerant to hydrogen peroxide. We demonstrate that the expression levels of the catalase KatB and the alkyl hydroperoxide reductase AhpB are increased in the aceF mutant. The simultaneous deletion of rsmY and rsmZ in the aceF mutant restored the expression levels of katB and ahpB, as well as bacterial susceptibility to hydrogen peroxide. Thus, we identify a novel role of AceF in the virulence and oxidative response of P. aeruginosa.
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Affiliation(s)
- Haozhou Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Yushan Xia
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Zhenyang Tian
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Wieslaw Swietnicki
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114 Wroclaw, Poland;
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (H.L.); (Y.X.); (Z.T.); (Y.J.); (F.B.); (Z.C.); (W.W.)
- Correspondence:
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13
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Hardy KS, Tuckey AN, Housley NA, Andrews J, Patel M, Al-Mehdi AB, Barrington RA, Cassel SL, Sutterwala FS, Audia JP. The Pseudomonas aeruginosa Type III Secretion System Exoenzyme Effector ExoU Induces Mitochondrial Damage in a Murine Bone Marrow-Derived Macrophage Infection Model. Infect Immun 2022; 90:e0047021. [PMID: 35130452 PMCID: PMC8929383 DOI: 10.1128/iai.00470-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that causes nosocomial pneumonia, urinary tract infections, and bacteremia. A hallmark of P. aeruginosa pathogenesis is disruption of host cell function by the type III secretion system (T3SS) and its cognate exoenzyme effectors. The T3SS effector ExoU is phospholipase A2 (PLA2) that targets the host cell plasmalemmal membrane to induce cytolysis and is an important virulence factor that mediates immune avoidance. In addition, ExoU has been shown to subvert the host inflammatory response in a noncytolytic manner. In primary bone marrow-derived macrophages (BMDMs), P. aeruginosa infection is sensed by the nucleotide-binding domain containing leucine-rich repeats-like receptor 4 (NLRC4) inflammasome, which triggers caspase-1 activation and inflammation. ExoU transiently inhibits NLRC4 inflammasome-mediated activation of caspase-1 and its downstream target, interleukin 1β (IL-1β), to suppress activation of inflammation. In the present study, we sought to identify additional noncytolytic virulence functions for ExoU and discovered an unexpected association between ExoU, host mitochondria, and NLRC4. We show that infection of BMDMs with P. aeruginosa strains expressing ExoU elicited mitochondrial oxidative stress. In addition, mitochondria and mitochondrion-associated membrane fractions enriched from infected cells exhibited evidence of autophagy activation, indicative of damage. The observation that ExoU elicited mitochondrial stress and damage suggested that ExoU may also associate with mitochondria during infection. Indeed, ExoU phospholipase A2 enzymatic activity was present in enriched mitochondria and mitochondrion-associated membrane fractions isolated from P. aeruginosa-infected BMDMs. Intriguingly, enriched mitochondria and mitochondrion-associated membrane fractions isolated from infected Nlrc4 homozygous knockout BMDMs displayed significantly lower levels of ExoU enzyme activity, suggesting that NLRC4 plays a role in the ExoU-mitochondrion association. These observations prompted us to assay enriched mitochondria and mitochondrion-associated membrane fractions for NLRC4, caspase-1, and IL-1β. NLRC4 and pro-caspase-1 were detected in enriched mitochondria and mitochondrion-associated membrane fractions isolated from noninfected BMDMs, and active caspase-1 and active IL-1β were detected in response to P. aeruginosa infection. Interestingly, ExoU inhibited mitochondrion-associated caspase-1 and IL-1β activation. The implications of ExoU-mediated effects on mitochondria and the NLRC4 inflammasome during P. aeruginosa infection are discussed.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Nicole A. Housley
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Joel Andrews
- Mitchell Cancer Institute, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Mita Patel
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Abu-Bakr Al-Mehdi
- Department of Pharmcology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Robert A. Barrington
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
| | - Suzanne L. Cassel
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Fayyaz S. Sutterwala
- Women’s Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, Alabama, USA
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, USA
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14
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Hardy KS, Tuckey AN, Renema P, Patel M, Al-Mehdi AB, Spadafora D, Schlumpf CA, Barrington RA, Alexeyev MF, Stevens T, Pittet JF, Wagener BM, Simmons JD, Alvarez DF, Audia JP. ExoU Induces Lung Endothelial Cell Damage and Activates Pro-Inflammatory Caspase-1 during Pseudomonas aeruginosa Infection. Toxins (Basel) 2022; 14:toxins14020152. [PMID: 35202178 PMCID: PMC8878379 DOI: 10.3390/toxins14020152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 12/24/2022] Open
Abstract
The Gram-negative, opportunistic pathogen Pseudomonas aeruginosa utilizes a type III secretion system to inject exoenzyme effectors into a target host cell. Of the four best-studied exoenzymes, ExoU causes rapid cell damage and death. ExoU is a phospholipase A2 (PLA2) that hydrolyses host cell membranes, and P. aeruginosa strains expressing ExoU are associated with poor outcomes in critically ill patients with pneumonia. While the effects of ExoU on lung epithelial and immune cells are well studied, a role for ExoU in disrupting lung endothelial cell function has only recently emerged. Lung endothelial cells maintain a barrier to fluid and protein flux into tissue and airspaces and regulate inflammation. Herein, we describe a pulmonary microvascular endothelial cell (PMVEC) culture infection model to examine the effects of ExoU. Using characterized P. aeruginosa strains and primary clinical isolates, we show that strains expressing ExoU disrupt PMVEC barrier function by causing substantial PMVEC damage and lysis, in a PLA2-dependent manner. In addition, we show that strains expressing ExoU activate the pro-inflammatory caspase-1, in a PLA2-dependent manner. Considering the important roles for mitochondria and oxidative stress in regulating inflammatory responses, we next examined the effects of ExoU on reactive oxygen species production. Infection of PMVECs with P. aeruginosa strains expressing ExoU triggered a robust oxidative stress compared to strains expressing other exoenzyme effectors. We also provide evidence that, intriguingly, ExoU PLA2 activity was detectable in mitochondria and mitochondria-associated membrane fractions isolated from P. aeruginosa-infected PMVECs. Interestingly, ExoU-mediated activation of caspase-1 was partially inhibited by reactive oxygen species scavengers. Together, these data suggest ExoU exerts pleiotropic effects on PMVEC function during P. aeruginosa infection that may inhibit endothelial barrier and inflammatory functions.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda N. Tuckey
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
| | - Phoibe Renema
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Biomedical Sciences, College of Allied Health, University of South Alabama Mobile, Mobile, AL 36688, USA
| | - Mita Patel
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Abu-Bakr Al-Mehdi
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Domenico Spadafora
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Cody A. Schlumpf
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
| | - Robert A. Barrington
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Flow Cytometry Core Lab, College of Medicine, University of South Alabama, Mobile, AL 36688, USA;
| | - Mikhail F. Alexeyev
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Troy Stevens
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Brant M. Wagener
- Department of Anesthesiology and Perioperative Medicine, Birmingham School of Medicine, University of Alabama, Birmingham, AL 35294, USA; (J.-F.P.); (B.M.W.)
| | - Jon D. Simmons
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Surgery, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Diego F. Alvarez
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Department of Physiology and Pharmacology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX 77304, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (K.S.H.); (A.N.T.); (C.A.S.); (R.A.B.)
- Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA; (P.R.); (M.P.); (A.-B.A.-M.); (M.F.A.); (T.S.); (J.D.S.); (D.F.A.)
- Correspondence:
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15
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Molecular Mechanisms Involved in Pseudomonas aeruginosa Bacteremia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:325-345. [DOI: 10.1007/978-3-031-08491-1_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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16
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Hardy KS, Tessmer MH, Frank DW, Audia JP. Perspectives on the Pseudomonas aeruginosa Type III Secretion System Effector ExoU and Its Subversion of the Host Innate Immune Response to Infection. Toxins (Basel) 2021; 13:880. [PMID: 34941717 PMCID: PMC8708460 DOI: 10.3390/toxins13120880] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/19/2021] [Accepted: 12/04/2021] [Indexed: 12/02/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic, Gram-negative pathogen and an important cause of hospital acquired infections, especially in immunocompromised patients. Highly virulent P. aeruginosa strains use a type III secretion system (T3SS) to inject exoenzyme effectors directly into the cytoplasm of a target host cell. P. aeruginosa strains that express the T3SS effector, ExoU, associate with adverse outcomes in critically ill patients with pneumonia, owing to the ability of ExoU to rapidly damage host cell membranes and subvert the innate immune response to infection. Herein, we review the structure, function, regulation, and virulence characteristics of the T3SS effector ExoU, a highly cytotoxic phospholipase A2 enzyme.
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Affiliation(s)
- Kierra S. Hardy
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, AL 36608, USA;
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36608, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Maxx H. Tessmer
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA;
| | - Dara W. Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jonathon P. Audia
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile, AL 36608, USA;
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36608, USA
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17
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Bagayoko S, Leon-Icaza SA, Pinilla M, Hessel A, Santoni K, Péricat D, Bordignon PJ, Moreau F, Eren E, Boyancé A, Naser E, Lefèvre L, Berrone C, Iakobachvili N, Metais A, Rombouts Y, Lugo-Villarino G, Coste A, Attrée I, Frank DW, Clevers H, Peters PJ, Cougoule C, Planès R, Meunier E. Host phospholipid peroxidation fuels ExoU-dependent cell necrosis and supports Pseudomonas aeruginosa-driven pathology. PLoS Pathog 2021; 17:e1009927. [PMID: 34516571 PMCID: PMC8460005 DOI: 10.1371/journal.ppat.1009927] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 09/23/2021] [Accepted: 08/29/2021] [Indexed: 11/20/2022] Open
Abstract
Regulated cell necrosis supports immune and anti-infectious strategies of the body; however, dysregulation of these processes drives pathological organ damage. Pseudomonas aeruginosa expresses a phospholipase, ExoU that triggers pathological host cell necrosis through a poorly characterized pathway. Here, we investigated the molecular and cellular mechanisms of ExoU-mediated necrosis. We show that cellular peroxidised phospholipids enhance ExoU phospholipase activity, which drives necrosis of immune and non-immune cells. Conversely, both the endogenous lipid peroxidation regulator GPX4 and the pharmacological inhibition of lipid peroxidation delay ExoU-dependent cell necrosis and improve bacterial elimination in vitro and in vivo. Our findings also pertain to the ExoU-related phospholipase from the bacterial pathogen Burkholderia thailandensis, suggesting that exploitation of peroxidised phospholipids might be a conserved virulence mechanism among various microbial phospholipases. Overall, our results identify an original lipid peroxidation-based virulence mechanism as a strong contributor of microbial phospholipase-driven pathology.
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Affiliation(s)
- Salimata Bagayoko
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Stephen Adonai Leon-Icaza
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Miriam Pinilla
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Audrey Hessel
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Karin Santoni
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - David Péricat
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Pierre-Jean Bordignon
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Flavie Moreau
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
- Level 3 Biosafety Animal Core facility, Anexplo platform, Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Elif Eren
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Aurélien Boyancé
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Emmanuelle Naser
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
- Cytometry & Imaging Core facility, Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Lise Lefèvre
- RESTORE institute, University of Toulouse, CNRS, Toulouse, France
| | - Céline Berrone
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
- Level 3 Biosafety Animal Core facility, Anexplo platform, Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Nino Iakobachvili
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Maastricht, The Netherlands
| | - Arnaud Metais
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Yoann Rombouts
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Geanncarlo Lugo-Villarino
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Agnès Coste
- RESTORE institute, University of Toulouse, CNRS, Toulouse, France
| | - Ina Attrée
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| | - Dara W. Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Hans Clevers
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, Netherlands
| | - Peter J. Peters
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Maastricht, The Netherlands
| | - Céline Cougoule
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Rémi Planès
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
| | - Etienne Meunier
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, Toulouse, France
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18
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The bacterial toxin ExoU requires a host trafficking chaperone for transportation and to induce necrosis. Nat Commun 2021; 12:4024. [PMID: 34188051 PMCID: PMC8241856 DOI: 10.1038/s41467-021-24337-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 06/11/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa can cause nosocomial infections, especially in ventilated or cystic fibrosis patients. Highly pathogenic isolates express the phospholipase ExoU, an effector of the type III secretion system that acts on plasma membrane lipids, causing membrane rupture and host cell necrosis. Here, we use a genome-wide screen to discover that ExoU requires DNAJC5, a host chaperone, for its necrotic activity. DNAJC5 is known to participate in an unconventional secretory pathway for misfolded proteins involving anterograde vesicular trafficking. We show that DNAJC5-deficient human cells, or Drosophila flies knocked-down for the DNAJC5 orthologue, are largely resistant to ExoU-dependent virulence. ExoU colocalizes with DNAJC5-positive vesicles in the host cytoplasm. DNAJC5 mutations preventing vesicle trafficking (previously identified in adult neuronal ceroid lipofuscinosis, a human congenital disease) inhibit ExoU-dependent cell lysis. Our results suggest that, once injected into the host cytoplasm, ExoU docks to DNAJC5-positive secretory vesicles to reach the plasma membrane, where it can exert its phospholipase activity Phospholipase ExoU from Pseudomonas aeruginosa acts on plasma membrane lipids in infected cells, causing membrane rupture and host cell necrosis. Here, Deruelle et al. show that once injected into the host cytoplasm, ExoU requires a host chaperone found on secretory vesicles to reach the plasma membrane and exerts its phospholipase activity.
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Morin CD, Déziel E, Gauthier J, Levesque RC, Lau GW. An Organ System-Based Synopsis of Pseudomonas aeruginosa Virulence. Virulence 2021; 12:1469-1507. [PMID: 34180343 PMCID: PMC8237970 DOI: 10.1080/21505594.2021.1926408] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Driven in part by its metabolic versatility, high intrinsic antibiotic resistance, and a large repertoire of virulence factors, Pseudomonas aeruginosa is expertly adapted to thrive in a wide variety of environments, and in the process, making it a notorious opportunistic pathogen. Apart from the extensively studied chronic infection in the lungs of people with cystic fibrosis (CF), P. aeruginosa also causes multiple serious infections encompassing essentially all organs of the human body, among others, lung infection in patients with chronic obstructive pulmonary disease, primary ciliary dyskinesia and ventilator-associated pneumonia; bacteremia and sepsis; soft tissue infection in burns, open wounds and postsurgery patients; urinary tract infection; diabetic foot ulcers; chronic suppurative otitis media and otitis externa; and keratitis associated with extended contact lens use. Although well characterized in the context of CF, pathogenic processes mediated by various P. aeruginosa virulence factors in other organ systems remain poorly understood. In this review, we use an organ system-based approach to provide a synopsis of disease mechanisms exerted by P. aeruginosa virulence determinants that contribute to its success as a versatile pathogen.
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Affiliation(s)
- Charles D Morin
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Jeff Gauthier
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Roger C Levesque
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Gee W Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, US
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20
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Pseudomonas aeruginosa Ventilator-Associated Pneumonia Rabbit Model for Preclinical Drug Development. Antimicrob Agents Chemother 2021; 65:e0272420. [PMID: 33972247 DOI: 10.1128/aac.02724-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development and validation of large animal models of Pseudomonas aeruginosa ventilator-associated pneumonia are needed for testing new drug candidates in a manner that mimics how they will be used clinically. We developed a new model in which rabbits were ventilated with low tidal volume and challenged with P. aeruginosa to recapitulate hallmark clinical features of acute respiratory distress syndrome (ARDS): acute lung injury and inflammation, progressive decrease in arterial oxygen partial pressure to fractional inspired oxygen PaO2:FiO2, leukopenia, neutropenia, thrombocytopenia, hyperlactatemia, severe hypotension, bacterial dissemination from lung to other organs, multiorgan dysfunction, and ultimately death. We evaluated the predictive power of this rabbit model for antibiotic efficacy testing by determining whether a humanized dosing regimen of meropenem, a potent antipseudomonal β-lactam antibiotic, when administered with or without intensive care unit (ICU)-supportive care (fluid challenge and norepinephrine), could halt or reverse natural disease progression. Our humanized meropenem dosing regimen produced a plasma concentration-time profile in the rabbit model similar to those reported in patients with ventilator-associated bacterial pneumonia. In this rabbit model, treatment with humanized meropenem and ICU-supportive care achieved the highest level of survival, halted the worsening of ARDS biomarkers, and reversed lethal hypotension, although treatment with humanized meropenem alone also conferred some protection compared to treatment with placebo (saline) alone or placebo plus ICU-supportive care. In conclusion, this rabbit model could help predict whether an antibiotic will be efficacious for the treatment of human ventilator-associated pneumonia.
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NAD(H)-mediated tetramerization controls the activity of Legionella pneumophila phospholipase PlaB. Proc Natl Acad Sci U S A 2021; 118:2017046118. [PMID: 34074754 DOI: 10.1073/pnas.2017046118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The virulence factor PlaB promotes lung colonization, tissue destruction, and intracellular replication of Legionella pneumophila, the causative agent of Legionnaires' disease. It is a highly active phospholipase exposed at the bacterial surface and shows an extraordinary activation mechanism by tetramer deoligomerization. To unravel the molecular basis for enzyme activation and localization, we determined the crystal structure of PlaB in its tetrameric form. We found that the tetramer is a dimer of identical dimers, and a monomer consists of an N-terminal α/β-hydrolase domain expanded by two noncanonical two-stranded β-sheets, β-6/β-7 and β-9/β-10. The C-terminal domain reveals a fold displaying a bilobed β-sandwich with a hook structure required for dimer formation and structural complementation of the enzymatic domain in the neighboring monomer. This highlights the dimer as the active form. Δβ-9/β-10 mutants showed a decrease in the tetrameric fraction and altered activity profiles. The variant also revealed restricted binding to membranes resulting in mislocalization and bacterial lysis. Unexpectedly, we observed eight NAD(H) molecules at the dimer/dimer interface, suggesting that these molecules stabilize the tetramer and hence lead to enzyme inactivation. Indeed, addition of NAD(H) increased the fraction of the tetramer and concomitantly reduced activity. Together, these data reveal structural elements and an unprecedented NAD(H)-mediated tetramerization mechanism required for spatial and enzymatic control of a phospholipase virulence factor. The allosteric regulatory process identified here is suited to fine tune PlaB in a way that protects Legionella pneumophila from self-inflicted lysis while ensuring its activity at the pathogen-host interface.
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Moir DT, Opperman TJ, Aron ZD, Bowlin TL. Adjunctive therapy for multidrug-resistant bacterial infections: Type III secretion system and efflux inhibitors. Drug Discov Today 2021; 26:2173-2181. [PMID: 33845218 DOI: 10.1016/j.drudis.2021.03.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/21/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
The increasing prevalence of multidrug-resistant (MDR) bacterial infections has created a crucial need for new therapeutics that avoid or minimize existing resistance mechanisms. In this review, we describe the development of novel classes of small-molecule adjunctive agents targeting either a bacterial virulence factor, the Pseudomonas aeruginosa type III secretion system (T3SS), or an intrinsic resistance factor, resistance-nodulation-cell division superfamily (RND) efflux pumps of the Enterobacteriaceae. These agents are designed to be administered with antibacterials to improve their efficacy. T3SS inhibition rescues host innate immune system cells from injection with bacterial toxins, whereas RND efflux pump inhibition increases antibiotic susceptibility, in both cases improving the efficacy of the combined antibacterial.
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Pont S, Fraikin N, Caspar Y, Van Melderen L, Attrée I, Cretin F. Bacterial behavior in human blood reveals complement evaders with some persister-like features. PLoS Pathog 2020; 16:e1008893. [PMID: 33326490 PMCID: PMC7773416 DOI: 10.1371/journal.ppat.1008893] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/30/2020] [Accepted: 11/03/2020] [Indexed: 12/17/2022] Open
Abstract
Bacterial bloodstream infections (BSI) are a major health concern and can cause up to 40% mortality. Pseudomonas aeruginosa BSI is often of nosocomial origin and is associated with a particularly poor prognosis. The mechanism of bacterial persistence in blood is still largely unknown. Here, we analyzed the behavior of a cohort of clinical and laboratory Pseudomonas aeruginosa strains in human blood. In this specific environment, complement was the main defensive mechanism, acting either by direct bacterial lysis or by opsonophagocytosis, which required recognition by immune cells. We found highly variable survival rates for different strains in blood, whatever their origin, serotype, or the nature of their secreted toxins (ExoS, ExoU or ExlA) and despite their detection by immune cells. We identified and characterized a complement-tolerant subpopulation of bacterial cells that we named “evaders”. Evaders shared some features with bacterial persisters, which tolerate antibiotic treatment. Notably, in bi-phasic killing curves, the evaders represented 0.1–0.001% of the initial bacterial load and displayed transient tolerance. However, the evaders are not dormant and require active metabolism to persist in blood. We detected the evaders for five other major human pathogens: Acinetobacter baumannii, Burkholderia multivorans, enteroaggregative Escherichia coli, Klebsiella pneumoniae, and Yersinia enterocolitica. Thus, the evaders could allow the pathogen to persist within the bloodstream, and may be the cause of fatal bacteremia or dissemination, in particular in the absence of effective antibiotic treatments. Blood infections by antibiotic resistant bacteria, notably Pseudomonas aeruginosa, are major concerns in hospital settings. The complex interplay between P. aeruginosa and the innate immune system in the context of human blood is still poorly understood. By studying the behavior of various P. aeruginosa strains in human whole blood and plasma, we showed that bacterial strains display different rate of tolerance to the complement system. Despite the complement microbicide activity, most bacteria withstand elimination through phenotypic heterogeneity creating a tiny (<0.1%) subpopulation of transiently tolerant evaders able to persist in plasma. This phenotypic heterogeneity thus prevents total elimination of the pathogen from the circulation, and represents a new strategy to disseminate within the organism.
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Affiliation(s)
- Stéphane Pont
- Université Grenoble Alpes, Bacterial Pathogenesis and Cellular Responses team, CNRS ERL5261, CEA IRIG-BCI, INSERM UMR1036, Grenoble, France
| | - Nathan Fraikin
- Université Libre de Bruxelles, Department of Molecular Biology, Cellular & Molecular Microbiology, Gosselies, Belgium
| | - Yvan Caspar
- Centre Hospitalier Universitaire Grenoble Alpes, Laboratoire de bactériologie-hygiène hospitalière, Grenoble, France
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Laurence Van Melderen
- Université Libre de Bruxelles, Department of Molecular Biology, Cellular & Molecular Microbiology, Gosselies, Belgium
| | - Ina Attrée
- Université Grenoble Alpes, Bacterial Pathogenesis and Cellular Responses team, CNRS ERL5261, CEA IRIG-BCI, INSERM UMR1036, Grenoble, France
- * E-mail: (FC); (IA)
| | - François Cretin
- Université Grenoble Alpes, Bacterial Pathogenesis and Cellular Responses team, CNRS ERL5261, CEA IRIG-BCI, INSERM UMR1036, Grenoble, France
- * E-mail: (FC); (IA)
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Armentrout EI, Kundracik EC, Rietsch A. Cell-type-specific hypertranslocation of effectors by the Pseudomonas aeruginosa type III secretion system. Mol Microbiol 2020; 115:305-319. [PMID: 33012037 DOI: 10.1111/mmi.14617] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/22/2020] [Indexed: 12/23/2022]
Abstract
Many Gram-negative pathogens use a type III secretion system (T3SS) to promote disease by injecting effector proteins into host cells. Common to many T3SSs is that injection of effector proteins is feedback inhibited. The mechanism of feedback inhibition and its role in pathogenesis are unclear. In the case of P. aeruginosa, the effector protein ExoS is central to limiting effector injection. ExoS is bifunctional, with an amino-terminal RhoGAP and a carboxy-terminal ADP-ribosyltransferase domain. We demonstrate that both domains are required to fully feedback inhibit effector injection. The RhoGAP-, but not the ADP-ribosyltransferase domain of the related effector protein ExoT also participates. Feedback inhibition does not involve translocator insertion nor pore-formation. Instead, feedback inhibition is due, in part, to a loss of the activating trigger for effector injection, and likely also decreased translocon stability. Surprisingly, feedback inhibition is abrogated in phagocytic cells. The lack of feedback inhibition in these cells requires phagocytic uptake of the bacteria, but cannot be explained through acidification of the phagosome or calcium limitation. Given that phagocytes are crucial for controlling P. aeruginosa infections, our data suggest that feedback inhibition allows P. aeruginosa to direct its effector arsenal against the cell types most damaging to its survival.
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Affiliation(s)
- Erin I Armentrout
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - Emma C Kundracik
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
| | - Arne Rietsch
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, USA
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Bouillot S, Pont S, Gallet B, Moriscot C, Deruelle V, Attrée I, Huber P. Inflammasome activation by Pseudomonas aeruginosa's ExlA pore-forming toxin is detrimental for the host. Cell Microbiol 2020; 22:e13251. [PMID: 32779854 DOI: 10.1111/cmi.13251] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/24/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
During acute Pseudomonas aeruginosa infection, the inflammatory response is essential for bacterial clearance. Neutrophil recruitment can be initiated following the assembly of an inflammasome within sentinel macrophages, leading to activation of caspase-1, which in turn triggers macrophage pyroptosis and IL-1β/IL-18 maturation. Inflammasome formation can be induced by a number of bacterial determinants, including Type III secretion systems (T3SSs) or pore-forming toxins, or, alternatively, by lipopolysaccharide (LPS) via caspase-11 activation. Surprisingly, previous studies indicated that a T3SS-induced inflammasome increased pathogenicity in mouse models of P. aeruginosa infection. Here, we investigated the immune reaction of mice infected with a T3SS-negative P. aeruginosa strain (IHMA879472). Virulence of this strain relies on ExlA, a secreted pore-forming toxin. IHMA879472 promoted massive neutrophil infiltration in infected lungs, owing to efficient priming of toll-like receptors, and thus enhanced the expression of inflammatory proteins including pro-IL-1β and TNF-α. However, mature-IL-1β and IL-18 were undetectable in wild-type mice, suggesting that ExlA failed to effectively activate caspase-1. Nevertheless, caspase-1/11 deficiency improved survival following infection with IHMA879472, as previously described for T3SS+ bacteria. We conclude that the detrimental effect associated with the ExlA-induced inflammasome is probably not due to hyperinflammation, rather it stems from another inflammasome-dependent process.
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Affiliation(s)
- Stéphanie Bouillot
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Stéphane Pont
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Benoit Gallet
- Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Christine Moriscot
- Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Vincent Deruelle
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Ina Attrée
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Philippe Huber
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble-Alpes, Grenoble, France
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26
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Cui Z, Dang G, Song N, Cui Y, Li Z, Zang X, Liu H, Wang Z, Liu S. Rv3091, An Extracellular Patatin-Like Phospholipase in Mycobacterium tuberculosis, Prolongs Intracellular Survival of Recombinant Mycolicibacterium smegmatis by Mediating Phagosomal Escape. Front Microbiol 2020; 11:2204. [PMID: 33042041 PMCID: PMC7517356 DOI: 10.3389/fmicb.2020.532371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/19/2020] [Indexed: 12/02/2022] Open
Abstract
Patatin-like phospholipases (PLPs) are important virulence factors of many pathogens. However, there are no prevailing studies regarding PLPs as a virulence factor of Mycobacterium tuberculosis (Mtb). Analysis of Rv3091, a putative protein of Mtb, shows that it belongs to the PLPs family. Here, we cloned and expressed the rv3091 gene in Mycobacterium smegmatis and, subsequently, conducted protein purification and characterization. We show that it possesses phospholipase A1, phospholipase A2, and lipase activity. We confirm the putative active site residues, namely, Ser214 and Asp407, using site directed mutagenesis. The Rv3091 is an extracellular protein that alters the colony morphology of M. smegmatis. The presence of Rv3091 enhances the intracellular survival capability of M. smegmatis in murine peritoneal macrophages. Additionally, it promotes M. smegmatis phagosomal escape from macrophages. Moreover, Rv3091 significantly increased the survival of M. smegmatis and aggravated lesions in C57BL/6 J murine lungs in vivo. Taken together, our results indicate that Rv3091 as an extracellular PLP that is critical to the pathogenicity of mycobacterium as it allows mycobacterium to utilize phospholipids for its growth and provides resistance to phagosome killing, resulting in its enhanced intracellular survival.
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Affiliation(s)
- Ziyin Cui
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Guanghui Dang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ningning Song
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yingying Cui
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhe Li
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xinxin Zang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hongxiu Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhongxing Wang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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27
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Pan X, Fan Z, Chen L, Liu C, Bai F, Wei Y, Tian Z, Dong Y, Shi J, Chen H, Jin Y, Cheng Z, Jin S, Lin J, Wu W. PvrA is a novel regulator that contributes to Pseudomonas aeruginosa pathogenesis by controlling bacterial utilization of long chain fatty acids. Nucleic Acids Res 2020; 48:5967-5985. [PMID: 32406921 PMCID: PMC7293031 DOI: 10.1093/nar/gkaa377] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 12/19/2022] Open
Abstract
During infection of a host, Pseudomonas aeruginosa orchestrates global gene expression to adapt to the host environment and counter the immune attacks. P. aeruginosa harbours hundreds of regulatory genes that play essential roles in controlling gene expression. However, their contributions to the bacterial pathogenesis remain largely unknown. In this study, we analysed the transcriptomic profile of P. aeruginosa cells isolated from lungs of infected mice and examined the roles of upregulated regulatory genes in bacterial virulence. Mutation of a novel regulatory gene pvrA (PA2957) attenuated the bacterial virulence in an acute pneumonia model. Chromatin immunoprecipitation (ChIP)-Seq and genetic analyses revealed that PvrA directly regulates genes involved in phosphatidylcholine utilization and fatty acid catabolism. Mutation of the pvrA resulted in defective bacterial growth when phosphatidylcholine or palmitic acid was used as the sole carbon source. We further demonstrated that palmitoyl coenzyme A is a ligand for the PvrA, enhancing the binding affinity of PvrA to its target promoters. An arginine residue at position 136 was found to be essential for PvrA to bind palmitoyl coenzyme A. Overall, our results revealed a novel regulatory pathway that controls genes involved in phosphatidylcholine and fatty acid utilization and contributes to the bacterial virulence.
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Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Lei Chen
- Department of Plant Biology and Ecology, College of Life Science Nankai University, Tianjin 300071 China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yu Wei
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Zhenyang Tian
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yuanyuan Dong
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jianping Lin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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28
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Lucas R, Hadizamani Y, Gonzales J, Gorshkov B, Bodmer T, Berthiaume Y, Moehrlen U, Lode H, Huwer H, Hudel M, Mraheil MA, Toque HAF, Chakraborty T, Hamacher J. Impact of Bacterial Toxins in the Lungs. Toxins (Basel) 2020; 12:toxins12040223. [PMID: 32252376 PMCID: PMC7232160 DOI: 10.3390/toxins12040223] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial toxins play a key role in the pathogenesis of lung disease. Based on their structural and functional properties, they employ various strategies to modulate lung barrier function and to impair host defense in order to promote infection. Although in general, these toxins target common cellular signaling pathways and host compartments, toxin- and cell-specific effects have also been reported. Toxins can affect resident pulmonary cells involved in alveolar fluid clearance (AFC) and barrier function through impairing vectorial Na+ transport and through cytoskeletal collapse, as such, destroying cell-cell adhesions. The resulting loss of alveolar-capillary barrier integrity and fluid clearance capacity will induce capillary leak and foster edema formation, which will in turn impair gas exchange and endanger the survival of the host. Toxins modulate or neutralize protective host cell mechanisms of both the innate and adaptive immunity response during chronic infection. In particular, toxins can either recruit or kill central players of the lung's innate immune responses to pathogenic attacks, i.e., alveolar macrophages (AMs) and neutrophils. Pulmonary disorders resulting from these toxin actions include, e.g., acute lung injury (ALI), the acute respiratory syndrome (ARDS), and severe pneumonia. When acute infection converts to persistence, i.e., colonization and chronic infection, lung diseases, such as bronchitis, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) can arise. The aim of this review is to discuss the impact of bacterial toxins in the lungs and the resulting outcomes for pathogenesis, their roles in promoting bacterial dissemination, and bacterial survival in disease progression.
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Affiliation(s)
- Rudolf Lucas
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
| | - Yalda Hadizamani
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
| | - Joyce Gonzales
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Thomas Bodmer
- Labormedizinisches Zentrum Dr. Risch, Waldeggstr. 37 CH-3097 Liebefeld, Switzerland;
| | - Yves Berthiaume
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Ueli Moehrlen
- Pediatric Surgery, University Children’s Hospital, Zürich, Steinwiesstrasse 75, CH-8032 Zürch, Switzerland;
| | - Hartmut Lode
- Insitut für klinische Pharmakologie, Charité, Universitätsklinikum Berlin, Reichsstrasse 2, D-14052 Berlin, Germany;
| | - Hanno Huwer
- Department of Cardiothoracic Surgery, Voelklingen Heart Center, 66333 Voelklingen/Saar, Germany;
| | - Martina Hudel
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Mobarak Abu Mraheil
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Haroldo Alfredo Flores Toque
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Trinad Chakraborty
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Jürg Hamacher
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
- Medical Clinic V-Pneumology, Allergology, Intensive Care Medicine and Environmental Medicine, Faculty of Medicine, Saarland University, University Medical Centre of the Saarland, D-66421 Homburg, Germany
- Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, D-66421 Homburg, Germany
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
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29
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Pseudomonas aeruginosa ExsA Regulates a Metalloprotease, ImpA, That Inhibits Phagocytosis of Macrophages. Infect Immun 2019; 87:IAI.00695-19. [PMID: 31527124 DOI: 10.1128/iai.00695-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogenic bacterium whose type III secretion system (T3SS) plays a critical role in acute infections. Translocation of the T3SS effectors into host cells induces cytotoxicity. In addition, the T3SS promotes the intracellular growth of P. aeruginosa during host infections. The T3SS regulon genes are regulated by an AraC-type regulator, ExsA. In this study, we found that an extracellular metalloprotease encoded by impA (PA0572) is under the regulation of ExsA. An ExsA consensus binding sequence was identified upstream of the impA gene, and direct binding of the site by ExsA was demonstrated via an electrophoretic mobility shift assay. We further demonstrate that secreted ImpA cleaves the macrophage surface protein CD44, which inhibits the phagocytosis of the bacterial cells by macrophages. Combined, our results reveal a novel ExsA-regulated virulence factor that cooperatively inhibits the functions of macrophages with the T3SS.
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30
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Soares A, Roussel V, Pestel-Caron M, Barreau M, Caron F, Bouffartigues E, Chevalier S, Etienne M. Understanding Ciprofloxacin Failure in Pseudomonas aeruginosa Biofilm: Persister Cells Survive Matrix Disruption. Front Microbiol 2019; 10:2603. [PMID: 31798554 PMCID: PMC6864029 DOI: 10.3389/fmicb.2019.02603] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/28/2019] [Indexed: 12/22/2022] Open
Abstract
Biofilms are commonly recalcitrant to antibiotics, through incompletely elucidated mechanisms such as tolerance and persistence. We aimed at investigating how a Pseudomonas aeruginosa biofilm escapes ciprofloxacin treatment. P. aeruginosa PA14 in vitro mature biofilms were challenged with supra-MIC ciprofloxacin concentrations. Cell viability was quantified by fluorescein diacetate assay. Population dynamics were determined by counts of surviving culturable cells. Biofilms were analyzed using confocal laser scanning microscopy (CLSM), and the expression of genes involved in stringent response, toxin-antitoxin HigB/HigA, and type 3 secretion system (T3SS) was quantified by RT-qPCR in untreated and treated biofilms. Ciprofloxacin exposure resulted in an initial reduction of bacterial counts following a biphasic time-kill curve. After 24 h of treatment, the overall cell activity and the density of culturable cells significantly decreased as compared to untreated biofilm. No resistant mutant was isolated among the <1% surviving cells. Phenotypic adaptation toward persistence appeared to start after only 1 h of antibiotic exposure, by an overexpression of the genes involved in stringent response and in the toxin-antitoxin system, whereas the expression of genes encoding for the T3SS remained unchanged. After 4 h of ciprofloxacin exposure, stringent response genes returned to their basal level of expression. After a prolonged ciprofloxacin exposure, a deep alteration in the matrix structure that became thinner and lost mushroom-like aggregates was observed, in relation with reduced biovolumes of exopolysaccharides and extracellular DNA. These results support that ciprofloxacin might first induce the bacterial killing of most bacterial cells, but simultaneously activate stringent response mechanisms contributing to the switch of a subpopulation toward a persister phenotype. Once the persister phenotype is expressed, and despite an unexpected alteration of the biofilm matrix, ciprofloxacin fails to eradicate biofilm.
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Affiliation(s)
- Anaïs Soares
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - Valérie Roussel
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France
| | - Martine Pestel-Caron
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - Magalie Barreau
- EA 4312, LMSM, Normandie University, UNIROUEN, Evreux, France
| | - François Caron
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
| | | | | | - Manuel Etienne
- GRAM 2.0, EA 2656, Normandie University, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
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31
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Mesquita CS, Soares-Castro P, Faustino A, Santos HM, Capelo JL, Santos P. Identification of genomic loci associated with genotypic and phenotypic variation among Pseudomonas aeruginosa clinical isolates from pneumonia. Microb Pathog 2019; 136:103702. [PMID: 31472259 DOI: 10.1016/j.micpath.2019.103702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 11/19/2022]
Abstract
In this work, a genotype-phenotype survey of a highly diversified Pseudomonas aeruginosa collection was conducted, aiming to detail pathogen-associated scenarios that clinicians face nowadays. Genetic relation based on RAPD-PCR of 705 isolates, retrieved from 424 patients and several clinical contexts, reported an almost isolate-specific molecular-pattern. Pneumonia-associated isolates HB13 and HB15, clustered in the same RAPD-PCR group, were selected to evaluate the genomic background underlying their contrasting antibiotic resistance and virulence. The HB13 genome harbors antibiotic-inactivating enzymes-coding genes (e.g. aac(3)-Ia, arr, blaVIM-2) and single-nucleotide variations (SNVs) in antibiotic targets, likely accounting for its pan-resistance, whereas HB15 susceptibility correlated to predicted dysfunctional alleles. Isolate HB13 showed the unprecedented rhl-cluster absence and variations in other pathogen competitiveness contributors. Conversely, HB15 genome comprises exoenzyme-coding genes and SNVs linked to increased virulence. Secretome analysis identified signatures features with unknown function as potential novel pathogenic (e.g. a MATE-protein in HB13, a protease in HB15) and antibiotic resistance (a HlyD-like secretion protein in HB13) determinants. Detection of active prophages, proteases (including protease IV and alkaline metalloproteinase), a porin and a peptidase in HB15 highlights the secreted arsenal likely essential for its virulent behavior. The presented phenotype-genome association will contribute to the current knowledge on Pseudomonas aeruginosa pathogenomics.
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Affiliation(s)
- Cristina S Mesquita
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Pedro Soares-Castro
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Alberta Faustino
- Clinical Pathology Service, Hospital de Braga, 4710-243, Braga, Portugal
| | - Hugo M Santos
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Park, Rua dos Inventores, 2825-152, Caparica, Portugal
| | - José L Capelo
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Park, Rua dos Inventores, 2825-152, Caparica, Portugal
| | - Pedro Santos
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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Antibiotic resistance in Pseudomonas aeruginosa - Mechanisms, epidemiology and evolution. Drug Resist Updat 2019; 44:100640. [PMID: 31492517 DOI: 10.1016/j.drup.2019.07.002] [Citation(s) in RCA: 233] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Antibiotics are powerful drugs used in the treatment of bacterial infections. The inappropriate use of these medicines has driven the dissemination of antibiotic resistance (AR) in most bacteria. Pseudomonas aeruginosa is an opportunistic pathogen commonly involved in environmental- and difficult-to-treat hospital-acquired infections. This species is frequently resistant to several antibiotics, being in the "critical" category of the WHO's priority pathogens list for research and development of new antibiotics. In addition to a remarkable intrinsic resistance to several antibiotics, P. aeruginosa can acquire resistance through chromosomal mutations and acquisition of AR genes. P. aeruginosa has one of the largest bacterial genomes and possesses a significant assortment of genes acquired by horizontal gene transfer (HGT), which are frequently localized within integrons and mobile genetic elements (MGEs), such as transposons, insertion sequences, genomic islands, phages, plasmids and integrative and conjugative elements (ICEs). This genomic diversity results in a non-clonal population structure, punctuated by specific clones that are associated with significant morbidity and mortality worldwide, the so-called high-risk clones. Acquisition of MGEs produces a fitness cost in the host, that can be eased over time by compensatory mutations during MGE-host coevolution. Even though plasmids and ICEs are important drivers of AR, the underlying evolutionary traits that promote this dissemination are poorly understood. In this review, we provide a comprehensive description of the main strategies involved in AR in P. aeruginosa and the leading drivers of HGT in this species. The most recently developed genomic tools that allowed a better understanding of the features contributing for the success of P. aeruginosa are discussed.
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Botelho J, Grosso F, Peixe L. WITHDRAWN: Antibiotic resistance in Pseudomonas aeruginosa – mechanisms, epidemiology and evolution. Drug Resist Updat 2019. [DOI: 10.1016/j.drup.2019.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Xiao F, Cao B, Wang C, Guo X, Li M, Xing D, Hu X. Pathogen-Specific Polymeric Antimicrobials with Significant Membrane Disruption and Enhanced Photodynamic Damage To Inhibit Highly Opportunistic Bacteria. ACS NANO 2019; 13:1511-1525. [PMID: 30632740 DOI: 10.1021/acsnano.8b07251] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Highly pathogenic Gram-negative bacteria and their drug resistance are a severe public health threat with high mortality. Gram-negative bacteria are hard to kill due to the complex cell envelopes with low permeability and extra defense mechanisms. It is challenging to treat them with current strategies, mainly including antibiotics, peptides, polymers, and some hybrid materials, which still face the issue of drug resistance, limited antibacterial selectivity, and severe side effects. Together with precise bacteria targeting, synergistic therapeutic modalities, including physical membrane damage and photodynamic eradication, are promising to combat Gram-negative bacteria. Herein, pathogen-specific polymeric antimicrobials were formulated from amphiphilic block copolymers, poly(butyl methacrylate)- b-poly(2-(dimethylamino) ethyl methacrylate- co-eosin)- b-ubiquicidin, PBMA- b-P(DMAEMA- co-EoS)-UBI, in which pathogen-targeting peptide ubiquicidin (UBI) was tethered in the hydrophilic chain terminal, and Eosin-Y was copolymerized in the hydrophilic block. The micelles could selectively adhere to bacteria instead of mammalian cells, inserting into the bacteria membrane to induce physical membrane damage and out-diffusion of intracellular milieu. Furthermore, significant in situ generation of reactive oxygen species was observed upon light irradiation, achieving further photodynamic eradication. Broad-spectrum bacterial inhibition was demonstrated for the polymeric antimicrobials, especially highly opportunistic Gram-negative bacteria, such as Pseudomona aeruginosa ( P. aeruginosa) based on the synergy of physical destruction and photodynamic therapy, without detectable resistance. In vivo P. aeruginosa-infected knife injury model and burn model both proved good potency of bacteria eradication and promoted wound healing, which was comparable with commercial antibiotics, yet no risk of drug resistance. It is promising to hurdle the infection and resistance suffered from highly opportunistic bacteria.
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Affiliation(s)
- Fengfeng Xiao
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Bing Cao
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Congyu Wang
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Xujuan Guo
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Mengge Li
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
| | - Xianglong Hu
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science , South China Normal University , Guangzhou 510631 , China
- College of Biophotonics , South China Normal University , Guangzhou 510631 , China
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Botelho J, Grosso F, Peixe L. Unravelling the genome of a Pseudomonas aeruginosa isolate belonging to the high-risk clone ST235 reveals an integrative conjugative element housing a blaGES-6 carbapenemase. J Antimicrob Chemother 2018; 73:77-83. [PMID: 29029083 DOI: 10.1093/jac/dkx337] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/19/2017] [Indexed: 12/12/2022] Open
Abstract
Objectives In Pseudomonas aeruginosa, the blaGES-6 carbapenemase gene was previously associated with an In1076 class I integron. Here, we conducted a genome-based analysis and explored the genetic platform associated with the mobility of this gene. Methods WGS of a blaGES-6-harbouring P. aeruginosa isolate (FFUP_PS_690) was performed with Illumina HiSeq, de novo assembly was performed using SPAdes and subsequent bioinformatic analysis was performed concerning antibiotic resistance genes, virulence features and mobile genetic elements. Results The FFUP_PS_690 isolate belongs to the ST235 high-risk clone and houses a novel integrative conjugative element (ICE), hereby named ICEPae690. This clc-like ICE comprises the blaGES-6-harbouring In1076 integron and specific modules. An ExoU island A variant was also identified. Conclusions The presence of a 'hitch-hiking' blaGES-6-harbouring In1076 integron in an ICE and an exoU-carrying genomic island highlight the potential spread of these elements through conjugation and/or clonal expansion of the ST235 lineage.
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Affiliation(s)
- João Botelho
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Filipa Grosso
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Luísa Peixe
- UCIBIO/REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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Saputra IWAGM, Mertaniasih NM, Fatmawati NND. Positivity of ExoU Gene of Type III Secretion System and Fluoroquinolone Resistance of Psedomonas aeruginosa from Sputum of Nosocomial Pneumonia Patients in Sanglah Hospital, Bali. FOLIA MEDICA INDONESIANA 2018. [DOI: 10.20473/fmi.v54i2.8863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa is one of the Gram-negative rods bacteria that frequently cause nosocomial pneumonia. One of the main virulent effector proteins on Type III secretion system (TTSS) of P. aeruginosa is Exoenzyme U ( ExoU). ExoU works as a phospholipase A2 activity and exhibits lung tissue injury effect in pneumonia. As an antibiotic that has activity against P. aeruginosa, fluoroquinolone resistance has increased as many as three fold since the last decade. Infections caused by P. aeruginosa that are fluoroquinolone resistant and positive for ExoU gene show worse clinical outcome. The aim of this study was to determine the positivity of ExoU gene TTSS and fluoroquinolone resistance of P. aeruginosa that isolated from sputum of nosocomial pneumonia patients in Sanglah Hospital, Bali. P. aeruginosa isolated from sputum of patient that diagnosed as nosocomial pneumonia, isolates had been identified phenotypically by Vitek2 Compact system (bioMérieux, Inc., Marcy-l'Etoile - France), and then continued by genotypic detection by PCR. The susceptibility testing of P. aeruginosa isolates to Ciprofloxacin were conducted by Vitek2 Compact, whereas ExoU genes were detected by PCR. Fifty-three P. aeruginosa isolates were identified in this study, in which 35 isolates (66.1%) had ExoU gene and 22 isolates (41.5%) were resistant to Ciprofloxacin. Based on nosocomial pneumonia type, the highest proportion of isolates genotipically ExoU+ and phenotypically Ciprofloxacin were on VAP group accounted for 57.1% and 54.5%, respectively. Chi-square analysis showed significant correlation between Ciprofloxacin resistance and ExoU gene (p=0.001). As a conclusion, the positivity of ExoU+ isolates were more likely found in Ciprofloxacin resistant group.
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37
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Pseudomonas aeruginosa Effector ExoS Inhibits ROS Production in Human Neutrophils. Cell Host Microbe 2017; 21:611-618.e5. [PMID: 28494242 DOI: 10.1016/j.chom.2017.04.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 03/10/2017] [Accepted: 04/11/2017] [Indexed: 12/31/2022]
Abstract
Neutrophils are the first line of defense against bacterial infections, and the generation of reactive oxygen species is a key part of their arsenal. Pathogens use detoxification systems to avoid the bactericidal effects of reactive oxygen species. Here we demonstrate that the Gram-negative pathogen Pseudomonas aeruginosa is susceptible to reactive oxygen species but actively blocks the reactive oxygen species burst using two type III secreted effector proteins, ExoS and ExoT. ExoS ADP-ribosylates Ras and prevents it from interacting with and activating phosphoinositol-3-kinase (PI3K), which is required to stimulate the phagocytic NADPH-oxidase that generates reactive oxygen species. ExoT also affects PI3K signaling via its ADP-ribosyltransferase activity but does not act directly on Ras. A non-ribosylatable version of Ras restores reactive oxygen species production and results in increased bacterial killing. These findings demonstrate that subversion of the host innate immune response requires ExoS-mediated ADP-ribosylation of Ras in neutrophils.
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Kang D, Kirienko NV. High-Throughput Genetic Screen Reveals that Early Attachment and Biofilm Formation Are Necessary for Full Pyoverdine Production by Pseudomonas aeruginosa. Front Microbiol 2017; 8:1707. [PMID: 28928729 PMCID: PMC5591869 DOI: 10.3389/fmicb.2017.01707] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/23/2017] [Indexed: 01/14/2023] Open
Abstract
Pseudomonas aeruginosa is a re-emerging, multidrug-resistant, opportunistic pathogen that threatens the lives of immunocompromised patients, patients with cystic fibrosis, and those in critical care units. One of the most important virulence factors in this pathogen is the siderophore pyoverdine. Pyoverdine serves several critical roles during infection. Due to its extremely high affinity for ferric iron, pyoverdine gives the pathogen a significant advantage over the host in their competition for iron. In addition, pyoverdine can regulate the production of multiple bacterial virulence factors and perturb host mitochondrial homeostasis. Inhibition of pyoverdine biosynthesis decreases P. aeruginosa pathogenicity in multiple host models. To better understand the regulation of pyoverdine production, we developed a high-throughput genetic screen that uses the innate fluorescence of pyoverdine to identify genes necessary for its biosynthesis. A substantial number of hits showing severe impairment of pyoverdine production were in genes responsible for early attachment and biofilm formation. In addition to genetic disruption of biofilm, both physical and chemical perturbations also attenuated pyoverdine production. This regulatory relationship between pyoverdine and biofilm is particularly significant in the context of P. aeruginosa multidrug resistance, where the formation of biofilm is a key mechanism preventing access to antimicrobials and the immune system. Furthermore, we demonstrate that the biofilm inhibitor 2-amino-5,6-dimethylbenzimidazole effectively attenuates pyoverdine production and rescues Caenorhabditis elegans from P. aeruginosa-mediated pathogenesis. Our findings suggest that targeting biofilm formation in P. aeruginosa infections may have multiple therapeutic benefits and that employing an unbiased, systems biology-based approach may be useful for understanding the regulation of specific virulence factors and identifying novel anti-virulence therapeutics or new applications for existing therapies for P. aeruginosa infections.
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Affiliation(s)
- Donghoon Kang
- Department of Biosciences, Rice UniversityHouston, TX, United States
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Pazos MA, Lanter BB, Yonker LM, Eaton AD, Pirzai W, Gronert K, Bonventre JV, Hurley BP. Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration. PLoS Pathog 2017; 13:e1006548. [PMID: 28771621 PMCID: PMC5557605 DOI: 10.1371/journal.ppat.1006548] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/15/2017] [Accepted: 07/22/2017] [Indexed: 12/21/2022] Open
Abstract
Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment. Pseudomonas aeruginosa is an opportunistic pathogen that causes acute pneumonia in immune compromised patients, and infects 70–80% of patients suffering from cystic fibrosis. Infections can result in excessive airway inflammation, which lead to immune-mediated lung damage, in particular through the action of recruited white blood cells known as neutrophils. Certain strains of P. aeruginosa produce the exotoxin ExoU, which has been associated with increased virulence. ExoU causes host cell lysis by hydrolyzing host membrane lipids through its phospholipase activity. However, host phospholipases play a key role in immune signaling by mediating the production of lipids known as eicosanoids. We investigated whether separate from its cytolytic activity, ExoU could modulate host immune responses through its phospholipase activity by hijacking eicosanoid production. Using in vitro and in vivo models of neutrophil recruitment, we find that ExoU producing strains of P. aeruginosa elicit higher levels of the eicosanoid chemoattractant leukotriene B4 from migrated neutrophils. This results in increased neutrophil transepithelial migration. This work reveals a new mechanism for how bacterial pathogens alter our immune function, and highlights a new potential therapeutic strategy for moderating Pseudomonas pathogenesis in patients with cystic fibrosis and acute pneumonia.
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Affiliation(s)
- Michael A. Pazos
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bernard B. Lanter
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lael M. Yonker
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alex D. Eaton
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
| | - Waheed Pirzai
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
| | - Karsten Gronert
- Vision Science Program, School of Optometry, University of California at Berkeley, Berkeley, California, United States of America
| | - Joseph V. Bonventre
- Renal Division and Biomedical Engineering Division, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bryan P. Hurley
- Mucosal Immunology & Biology Research Center, Massachusetts General Hospital for Children, Boston, Massachusetts, United States of America
- Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Pan X, Dong Y, Fan Z, Liu C, Xia B, Shi J, Bai F, Jin Y, Cheng Z, Jin S, Wu W. In vivo Host Environment Alters Pseudomonas aeruginosa Susceptibility to Aminoglycoside Antibiotics. Front Cell Infect Microbiol 2017; 7:83. [PMID: 28352614 PMCID: PMC5348532 DOI: 10.3389/fcimb.2017.00083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 03/02/2017] [Indexed: 01/06/2023] Open
Abstract
During host infection, Pseudomonas aeruginosa coordinately regulates the expression of numerous genes to adapt to the host environment while counteracting host clearance mechanisms. As infected patients take antibiotics, the invading bacteria encounter antibiotics in the host milieu. P. aeruginosa is highly resistant to antibiotics due to multiple chromosomally encoded resistant determinants. And numerous in vitro studies have demonstrated the regulatory mechanisms of antibiotic resistance related genes in response to antibiotics. However, it is not well-known how host environment affects bacterial response to antibiotics. In this study, we found that P. aeruginosa cells directly isolated from mice lungs displayed higher susceptibility to tobramycin than in vitro cultured bacteria. In vitro experiments demonstrated that incubation with A549 and differentiated HL60 (dHL60) cells sensitized P. aeruginosa to tobramycin. Further studies revealed that reactive oxygen species produced by the host cells contributed to the increased bacterial susceptibility. At the same concentration of tobramycin, presence of A549 and dHL60 cells resulted in higher expression of heat shock proteins, which are known inducible by tobramycin. Further analyses revealed decreased membrane potential upon incubation with the host cells and modification of lipopolysaccharide, which contributed to the increased susceptibility to tobramycin. Therefore, our results demonstrate that contact with host cells increased bacterial susceptibility to tobramycin.
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Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yuanyuan Dong
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Bin Xia
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy and Life Sciences, Nankai University Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of FloridaGainesville, FL, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
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Weng Y, Chen F, Liu Y, Zhao Q, Chen R, Pan X, Liu C, Cheng Z, Jin S, Jin Y, Wu W. Pseudomonas aeruginosa Enolase Influences Bacterial Tolerance to Oxidative Stresses and Virulence. Front Microbiol 2016; 7:1999. [PMID: 28018326 PMCID: PMC5156722 DOI: 10.3389/fmicb.2016.01999] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 11/29/2016] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram negative opportunistic pathogenic bacterium, which causes acute and chronic infections. Upon entering the host, bacteria alter global gene expression to adapt to host environment and avoid clearance by the host. Enolase is a glycolytic enzyme involved in carbon metabolism. It is also a component of RNA degradosome, which is involved in RNA processing and gene regulation. Here, we report that enolase is required for the virulence of P. aeruginosa in a murine acute pneumonia model. Mutation of enolase coding gene (eno) increased bacterial susceptibility to neutrophil mediated killing, which is due to reduced tolerance to oxidative stress. Catalases and alkyl hydroperoxide reductases play a major role in protecting the cell from oxidative damages. In the eno mutant, the expression levels of catalases (KatA and KatB) were similar as those in the wild type strain in the presence of H2O2, however, the expression levels of alkyl hydroperoxide reductases (AhpB and AhpC) were significantly reduced. Overexpression of ahpB but not ahpC in the eno mutant fully restored the bacterial resistance to H2O2 as well as neutrophil mediated killing, and partially restored bacterial virulence in the murine acute pneumonia model. Therefore, we have identified a novel role of enolase in the virulence of P. aeruginosa.
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Affiliation(s)
- Yuding Weng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Fei Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yiwei Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Qiang Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Ronghao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, GainesvilleFL, USA
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
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Li M, Long Y, Liu Y, Liu Y, Chen R, Shi J, Zhang L, Jin Y, Yang L, Bai F, Jin S, Cheng Z, Wu W. HigB of Pseudomonas aeruginosa Enhances Killing of Phagocytes by Up-Regulating the Type III Secretion System in Ciprofloxacin Induced Persister Cells. Front Cell Infect Microbiol 2016; 6:125. [PMID: 27790409 PMCID: PMC5064212 DOI: 10.3389/fcimb.2016.00125] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/27/2016] [Indexed: 12/01/2022] Open
Abstract
Bacterial persister cells are dormant and highly tolerant to lethal antibiotics, which are believed to be the major cause of recurring and chronic infections. Activation of toxins of bacterial toxin-antitoxin systems inhibits bacterial growth and plays an important role in persister formation. However, little is known about the overall gene expression profile upon toxin activation. More importantly, how the dormant bacterial persisters evade host immune clearance remains poorly understood. Here we demonstrate that a Pseudomonas aeruginosa toxin-antitoxin system HigB-HigA is required for the ciprofloxacin induced persister formation. Transcriptome analysis of a higA::Tn mutant revealed up regulation of type III secretion systems (T3SS) genes. Overexpression of HigB increased the expression of T3SS genes as well as bacterial cytotoxicity. We further demonstrate that wild type bacteria that survived ciprofloxacin treatment contain higher levels of T3SS proteins and display increased cytotoxicity to macrophage compared to vegetative bacterial cells. These results suggest that P. aeruginosa accumulates T3SS proteins during persister formation, which can protect the persister cells from host clearance by efficiently killing host immune cells.
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Affiliation(s)
- Mei Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yuqing Long
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Ying Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yang Liu
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University Singapore, Singapore
| | - Ronghao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Lu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological UniversitySingapore, Singapore; School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological UniversitySingapore, Singapore
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy and Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of FloridaGainesville, FL, USA
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
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Park MH, Kim SY, Roh EY, Lee HS. Difference of Type 3 secretion system (T3SS) effector gene genotypes (exoU and exoS) and its implication to antibiotics resistances in isolates of Pseudomonas aeruginosa from chronic otitis media. Auris Nasus Larynx 2016; 44:258-265. [PMID: 27461174 DOI: 10.1016/j.anl.2016.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Type 3 secretion system (T3SS) is the most important virulence factor in Pseudomonas aeruginosa infection. Of the various T3SS effector genes, exoS and exoU showed mutually exclusive distributions, and these two genes showed varied virulence. In many pseudomonal infections, the distribution of these genes showed different pattern and it influenced severity of infection. This study was aimed to evaluate differences of virulence factors and antibiotics resistance between chronic otitis media and other body infection caused by P. aeruginosa. METHODS To estimate the prevalence of effector genes of T3SS, especially the distributions of exoS and exoU genes and their association with antibiotic resistance in COM, we compared the prevalence of T3SS genes in isolates from COM with those from lower respiratory infection and bacteremia. Other virulence genes, including groEL, pilA, ndvB, lasB, rhlI, and apr, were also studied to evaluate prevalence. These isolates were tested for antibiotic susceptibility, and we examined the association between antibiotic susceptibility and the prevalence of T3SS effector genes. RESULTS The COM group showed a significantly higher exoU-positive rate than the control group (70.6% vs. 6.7%; P<0.01). Furthermore, COM patients with exoU showed significant antibiotic resistance to ciprofloxacin and tobramycin (P=0.035), whereas there was no significant difference in the control group. CONCLUSIONS The high incidence of exoU-positive P. aeruginosa and ciprofloxacin resistance can explain the chronicity and intractability of infection in COM. Elucidation of this pathogenicity will facilitate the development of new treatment options for COM patients.
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Affiliation(s)
- Min-Hyun Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
| | - So Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
| | - Eun Yun Roh
- Department of Clinical Laboratory Medicine, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
| | - Ho Sun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea
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Abstract
Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases.
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45
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Chen G, Zhao Q, Zhu F, Chen R, Jin Y, Liu C, Pan X, Jin S, Wu W, Cheng Z. Oligoribonuclease is required for the type III secretion system and pathogenesis of Pseudomonas aeruginosa. Microbiol Res 2016; 188-189:90-96. [PMID: 27296966 DOI: 10.1016/j.micres.2016.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/29/2016] [Accepted: 05/01/2016] [Indexed: 11/16/2022]
Abstract
Oligoribonuclease (Orn) is a 3' to 5' exonuclease that degrades nanoRNAs, which can serve as primers for transcription initiation at a significant fraction of promoters. One of Orn's substrates, pGpG inhibits the enzymatic activity of EAL-domain containing phosphodiesterases (PDEs), thereby increasing intracellular cyclic-di-GMP (c-di-GMP) level. Here, we found that an orn mutant of Pseudomonas aeruginosa displayed reduced cytotoxicity, which was mainly due to deficient type III secretion system (T3SS). Given the importance of T3SS in pathogenicity, we examined the bacterial virulence in a mouse acute pneumonia model and found that the Δorn mutant was highly attenuated compared to the wild type PA14 strain. Overexpression of an EAL domain-containing PDE reduced the c-di-GMP level as well as biofilm formation in the Δorn mutant. However, no effect was observed on the expression of T3SS genes, suggesting that increased c-di-GMP level is not the solely cause of defective T3SS in the Δorn mutant. Overall, our results demonstrated an essential role of Orn in the expression of T3SS as well as pathogenesis of P. aeruginosa.
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Affiliation(s)
- Gukui Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qiang Zhao
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Feng Zhu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ronghao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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46
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Zuverink M, Barbieri JT. From GFP to β-lactamase: advancing intact cell imaging for toxins and effectors. Pathog Dis 2015; 73:ftv097. [PMID: 26500183 DOI: 10.1093/femspd/ftv097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/13/2022] Open
Abstract
Canonical reporters such as green fluorescent protein (GFP) and luciferase have assisted researchers in probing cellular pathways and processes. Prior research in pathogenesis depended on sensitivity of biochemical and biophysical techniques to identify effectors and elucidate entry mechanisms. Recently, the β-lactamase (βlac) reporter system has advanced toxin and effector reporting by permitting measurement of βlac delivery into the cytosol or host βlac expression in intact cells. βlac measurement in cells was facilitated by the development of the fluorogenic substrate, CCF2-AM, to identify novel effectors, target cells, and domains involved in bacterial pathogenesis. The assay is also adaptable for high-throughput screening of small molecule inhibitors against toxins, providing information on mechanism and potential therapeutic agents. The versatility and limitations of the βlac reporter system as applied to toxins and effectors are discussed in this review.
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Affiliation(s)
- Madison Zuverink
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
| | - Joseph T Barbieri
- Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, WI 53226, USA
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47
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Affiliation(s)
- Roger D. Pechous
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - William E. Goldman
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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48
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Kondakova T, D'Heygère F, Feuilloley MJ, Orange N, Heipieper HJ, Duclairoir Poc C. Glycerophospholipid synthesis and functions in Pseudomonas. Chem Phys Lipids 2015; 190:27-42. [PMID: 26148574 DOI: 10.1016/j.chemphyslip.2015.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 11/25/2022]
Abstract
The genus Pseudomonas is one of the most heterogeneous groups of eubacteria, presents in all major natural environments and in wide range of associations with plants and animals. The wide distribution of these bacteria is due to the use of specific mechanisms to adapt to environmental modifications. Generally, bacterial adaptation is only considered under the aspect of genes and protein expression, but lipids also play a pivotal role in bacterial functioning and homeostasis. This review resumes the mechanisms and regulations of pseudomonal glycerophospholipid synthesis, and the roles of glycerophospholipids in bacterial metabolism and homeostasis. Recently discovered specific pathways of P. aeruginosa lipid synthesis indicate the lineage dependent mechanisms of fatty acids homeostasis. Pseudomonas glycerophospholipids ensure structure functions and play important roles in bacterial adaptation to environmental modifications. The lipidome of Pseudomonas contains a typical eukaryotic glycerophospholipid--phosphatidylcholine -, which is involved in bacteria-host interactions. The ability of Pseudomonas to exploit eukaryotic lipids shows specific and original strategies developed by these microorganisms to succeed in their infectious process. All compiled data provide the demonstration of the importance of studying the Pseudomonas lipidome to inhibit the infectious potential of these highly versatile germs.
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Affiliation(s)
- Tatiana Kondakova
- Normandie University of Rouen, Laboratory of Microbiology Signals and Microenvironment (LMSM), EA 4312, 55 rue St. Germain, 27000 Evreux, France
| | - François D'Heygère
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45071 Orléans, France
| | - Marc J Feuilloley
- Normandie University of Rouen, Laboratory of Microbiology Signals and Microenvironment (LMSM), EA 4312, 55 rue St. Germain, 27000 Evreux, France
| | - Nicole Orange
- Normandie University of Rouen, Laboratory of Microbiology Signals and Microenvironment (LMSM), EA 4312, 55 rue St. Germain, 27000 Evreux, France
| | - Hermann J Heipieper
- Department of Environmental Biotechnology, UFZ Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
| | - Cécile Duclairoir Poc
- Normandie University of Rouen, Laboratory of Microbiology Signals and Microenvironment (LMSM), EA 4312, 55 rue St. Germain, 27000 Evreux, France.
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49
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The Role of ExoS in Dissemination of Pseudomonas aeruginosa during Pneumonia. PLoS Pathog 2015; 11:e1004945. [PMID: 26090668 PMCID: PMC4474835 DOI: 10.1371/journal.ppat.1004945] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 05/11/2015] [Indexed: 01/11/2023] Open
Abstract
Hospital-acquired pneumonia is associated with high rates of morbidity and mortality, and dissemination to the bloodstream is a recognized risk factor for particularly poor outcomes. Yet the mechanism by which bacteria in the lungs gain access to the bloodstream remains poorly understood. In this study, we used a mouse model of Pseudomonas aeruginosa pneumonia to examine this mechanism. P. aeruginosa uses a type III secretion system to deliver effector proteins such as ExoS directly into the cytosol of eukaryotic cells. ExoS, a bi-functional GTPase activating protein (GAP) and ADP-ribosyltransferase (ADPRT), inhibits phagocytosis during pneumonia but has also been linked to a higher incidence of dissemination to the bloodstream. We used a novel imaging methodology to identify ExoS intoxicated cells during pneumonia and found that ExoS is injected into not only leukocytes but also epithelial cells. Phagocytic cells, primarily neutrophils, were targeted for injection with ExoS early during infection, but type I pneumocytes became increasingly injected at later time points. Interestingly, injection of these pneumocytes did not occur randomly but rather in discrete regions, which we designate ““fields of cell injection” (FOCI). These FOCI increased in size as the infection progressed and contained dead type I pneumocytes. Both of these phenotypes were attenuated in infections caused by bacteria secreting ADPRT-deficient ExoS, indicating that FOCI growth and type I pneumocyte death were dependent on the ADPRT activity of ExoS. During the course of infection, increased FOCI size was associated with enhanced disruption of the pulmonary-vascular barrier and increased bacterial dissemination into the blood, both of which were also dependent on the ADPRT activity of ExoS. We conclude that the ADPRT activity of ExoS acts upon type I pneumocytes to disrupt the pulmonary-vascular barrier during P. aeruginosa pneumonia, leading to bacterial dissemination. Dissemination to the bloodstream is a poor prognostic sign in patients with hospital-acquired pneumonia, yet the mechanism by which this occurs is poorly understood. To begin to address this issue, we have used a mouse model of P. aeruginosa pneumonia to study the mechanism by which the type-III-secreted effector protein ExoS enhances bacterial dissemination. We show that intoxication of type I pneumocytes by ExoS leads to cell death and disruption of the pulmonary-vascular barrier, allowing bacterial dissemination into the bloodstream. These effects required the ADP-ribosyltransferase activity of ExoS, as strains secreting an ExoS variant lacking this activity demonstrated reduced type I pneumocytes death and pulmonary-vascular breakdown. This study indicates that inhibitors of the ADP-ribosyltransferase activity of ExoS could serve as novel therapeutics for the prevention of bacteremic pneumonia.
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50
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da Cunha LG, Ferreira MF, de Moraes JA, Reis PA, Castro-Faria-Neto HC, Barja-Fidalgo C, Plotkowski MC, Saliba AM. ExoU-induced redox imbalance and oxidative stress in airway epithelial cells during Pseudomonas aeruginosa pneumosepsis. Med Microbiol Immunol 2015; 204:673-80. [PMID: 25904542 PMCID: PMC7100071 DOI: 10.1007/s00430-015-0418-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 04/12/2015] [Indexed: 12/14/2022]
Abstract
ExoU is a potent proinflammatory toxin produced by Pseudomonas aeruginosa, a major agent of severe lung infection and sepsis. Because inflammation is usually associated with oxidative stress, we investigated the effect of ExoU on free radical production and antioxidant defense mechanisms during the course of P. aeruginosa infection. In an experimental model of acute pneumonia, ExoU accounted for increased lipid peroxidation in mice lungs as soon as 3 h after intratracheal instillation of PA103 P. aeruginosa strain. The contribution of airway cells to the generation of a redox imbalance was assessed by in vitro tests carried out with A549 airway epithelial cells. Cultures infected with the ExoU-producing PA103 P. aeruginosa strain produced significantly increased concentrations of lipid hydroperoxides, 8-isoprostane, reactive oxygen intermediates, peroxynitrite and nitric oxide (NO), when compared to cells infected with exoU-deficient mutants. Overproduction of NO by PA103-infected cells likely resulted from overexpression of both inducible and endothelial NO synthase isoforms. PA103 infection was also associated with a significantly increased activity of superoxide dismutase (SOD) and decreased levels of reduced glutathione (GSH), a major antioxidant compound. Our findings unveil another potential mechanism of tissue damage during infection by ExoU-producing P. aeruginosa strains.
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Affiliation(s)
- Luiz Gonzaga da Cunha
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87, Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, 20.551-030, Brazil
| | - Miriam Francisca Ferreira
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87, Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, 20.551-030, Brazil
| | - João Alfredo de Moraes
- Laboratório de Farmacologia Celular e Molecular, Departamento de Biologia Celular, IBRAG, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Patricia Alves Reis
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | | | - Christina Barja-Fidalgo
- Laboratório de Farmacologia Celular e Molecular, Departamento de Biologia Celular, IBRAG, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Maria-Cristina Plotkowski
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87, Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, 20.551-030, Brazil
| | - Alessandra Mattos Saliba
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87, Fundos, 3° andar, Vila Isabel, Rio de Janeiro, RJ, 20.551-030, Brazil.
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